hypobiosis Flashcards
1
Q
what is hypobiosis
A
state in which larvae of some nematodes stop developing in the host and become dormant. (requires the correct stimuli)
2
Q
how does hypobiosis occur
A
- seasonal changes
- host immune responses
- developmental ques within the parasite
3
Q
what are the benefits of hypobiosis
A
- evade host immune response
- synchronize with favourable environmental conditions
- allows host to not become overrun
4
Q
name 2 immune evasion mechanisms used by nematodes
A
- hypobiosis
- immuno-suppression
- (production of cuticular proteins)
- neonatal immunological unresponsiveness
- concomitant immunity
- stimulation of polyclonal immunoglobulin
5
Q
how do nematodes use immunosuppresion to evade host immune response
A
ostertagia:
- L4 and adult supress T cell division
- dendritic cells and macrophages which present ostertagia antigens induce regulatory supressor T cells
- the production of many cytokines is decreased in calves challenged with ostertagia
- transforming growth factor beta is active and may suppress other cytokines
